This invention relates to a movable arrangement for inspecting pipes to detect interior leaks, having two mirror-inverted sections, each with at least one clamping device and at least one pair of runners, a pneumatic pressure fluid source, an inspection arrangement and a control arrangement.
Arrangements of this type are required for testing pipes, such as drinking-water pipes, pipelines or sewage pipes which are otherwise not accessible and are, for example, dug into the ground. By means of an inspection device, such as a television camera with the pertaining lighting, the interior walls of the pipes may be examined for damage. Possible leaks may also be detected by the fact that, after an advance within the pipe, an arrangement temporarily seals off a portion of the pipe to be inspected so that this portion can be subjected to an increased pressure, and a pressure drop during a preset time points to a leakage in the pipe. In order to be able to test longer pipes, it is necessary to move the arrangement forward inside the pipe in each case by a preset distance, and then to seal off a new portion of the pipe for a specified time period. Also, to examine pipes of different diameters by means of a single arrangement, different distances must be bridged and possibly sealed off between the outer circumference of the arrangement and the interior wall of the pipe.
To inspect the pipe without omitting gaps, precise positioning of the arrangement and a precisely controlled advance and position indication are essential, especially to facilitate easy later location of determined leak points by a corresponding repair device.
It is an object of the invention to provide a movable arrangement for testing the interior of pipes, which can be precisely positioned at any point, has a simple construction and permits smooth advance, independent of the load.
This and other objects and advantages are achieved by the inspection arrangement according to the invention, which comprises two sections, each having an outer cylinder, a disposable intermediate cylinder arranged concentrically in the outer cylinder, and a displaceable inner cylinder which is concentrically arranged in the intermediate cylinder. The two inner cylinders of the two sections are connected with a common pneumatic pressure fluid source, and each section is also connected with a hydraulic switching circuit.
The movable testing arrangement according to the invention offers the advantage that the pneumatic energy provided by the pneumatic pressure source which is used to check pipes for leaks can also used to advance the two sections, which can be moved relative to one another. Since the two sections are connected with separate, but identical, hydraulic switching circuits, movements of the center and inner cylinders disposed in the outer cylinder can be controlled sensitively and without jolts. As a result, a moving speed is achieved which is almost independent of the load.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.